Current opinion in general surgery最新文献

Improvements in surgical management and intensive care therapy have enabled many patients to initially survive severe life-threatening trauma or major surgical procedures only to die after delayed bouts of sepsis. This paper reviews literature published within the past year on the effects of nutrient substitution on malnutrition, injury, and the host immune response. Topics discussed include immunodeficiencies in trauma and malnutrition, immunomodulation by nutrition, and parenteral versus enteral nutrition. We also discuss the roles of arginine, glutamine, omega-3 fatty acids, and dietary nucleotides in the host immune response.

Stress induces a hypermetabolic state of increased urinary nitrogen loss and increased metabolic rate. The principal reason for such a response is the mobilization of amino acids and the production of glucose to provide energy for the cells involved in the host immune response and wound repair. The endocrine hormones, eg, cortisol, the catecholamines, and glucagon, are largely responsible for these effects. Insulin and growth hormone administration can produce anabolic effects to block the loss of body protein. Administration of specific amino acids, such as glutamine, also appears to be beneficial. However, the hypermetabolic state goes beyond derangement of endocrine hormone levels. Although the cytokines are also important mediators, it is not clear how these mediators, in concert with hormonal changes, produce all of the manifestations of the hypermetabolic state seen in stress.

For melanomas less than 1 mm thick, a 1-cm margin is considered adequate by most authors. For melanomas 1 to 4 mm thick, the results of the Intergroup Melanoma Trial in the United States suggest that a 2-cm margin is adequate. European studies indicate that a 1-cm margin may be satisfactory for all melanomas 2 mm thick or less. Elective node dissection is not indicated for melanomas less than 1 mm thick. Survival benefit has not been shown in two prospective studies, although retrospective studies suggest that elective node dissection improves the survival of patients with intermediate melanomas 1 to 4 mm thick. Elective dissection is more likely to benefit patients at high risk of harboring microscopic disease in the regional nodes, such as men with melanomas 1 to 4 mm thick or women with 2- to 4-mm lesions. For melanomas thicker than 4 mm, elective dissection is generally not indicated, except for staging purposes in the context of a protocol because the predominant mode of dissemination in this group is hematogenous. Therapeutic dissection is indicated in all patients with clinically suspicious regional nodes and no evidence of distant dissemination. In doubtful cases, a biopsy of the node may be done, to be followed, if the results are positive, with the definitive procedure. Although the majority of these patients relapse, the surgical treatment offers appreciable 5-year survival rates which cannot, at present, be attained by other modalities. Some evidence suggests that prompt detection of palpable regional nodes and thorough dissection improve the survival rates.

Perianal complications of Crohn's disease are fairly common in the adult and pediatric populations. Transrectal ultrasonography is effective for the diagnosis and follow-up of patients with anorectal abscesses and fistulas in Crohn's disease. Metronidazole and 6-mercaptopurine therapy have been used effectively to treat perianal complications of Crohn's disease in the pediatric population. Asymptomatic perianal fistulas in a patient with Crohn's disease do not require treatment. If a fistula is symptomatic and involves only a small portion of the sphincter mechanism, conventional fistulotomy may be performed with good results. Complex fistulas that involve larger areas of the sphincter are best treated by optimizing medical management and seton placement. The management of rectovaginal fistulas in the presence of Crohn's disease is controversial. Conventional fistulotomy and transvaginal mucosal advancement flap with diverting ileostomy have been advocated as primary treatment modalities. Rectovaginal fistulas secondary to ulcerative colitis may be treated by ileoanal pouch anastomosis and primary repair.

Several large series have been reported describing extensive surgery for gallbladder cancer; prolonged survival, however, has not been shown compared with more conservative treatment. Although in the case of bile duct tumors, excision of adjoining structures might confer some benefit and further improvement might be seen by the use of radiotherapy. Accurate preoperative imaging is beginning to be beneficial in the selection of patients for the different modalities of treatment.

Differential diagnosis of endocrine neoplasms as benign or malignant is frequently extremely difficult. Similarly, assessing prognosis in cases of malignancy is problematic. Traditionally, histologic criteria, including grade of the tumor, architectural features, and cytologic appearance, have been used to predict biologic behavior. In addition, clinical scoring systems may be useful in assigning prognosis in individual cases. Examination of the DNA profile of individual cells by flow cytometry may correlate with the aggressiveness of the tumor. Recent developments in molecular genetics have yielded genetic markers that may be useful in diagnosis and prognosis as well as illuminating the pathogenesis of endocrine neoplasia. This review summarizes the status of traditional and newer methods of pathologic interpretation of endocrine neoplasms. In general, the most accurate assessment of these tumors is derived from consideration of a collage of the clinical and pathologic criteria discussed herein.

Progress in techniques of diagnosing gastric cancer has made it possible to detect small lesions. Because of this advance, mass screenings for gastric cancer have been encouraged. Early gastric cancers have reached more than 30% of all gastric cancers at many hospitals in Japan. However, more than 50% of patients with gastric cancer have advanced cases. To detect early gastric cancer and to treat advanced cancer are both important clinically. This paper reviews studies of special interest in these areas.

Small bowel tumors include adenocarcinomas, carcinoids, lymphomas, and sarcomas, as well as a variety of benign polyps, which should be excised to rule out malignancy. Although small bowel tumors are traditionally difficult to diagnose, a heightened index of suspicion should be combined with improved diagnostic techniques to increase yield and decrease delays in identification. The management of bioactive carcinoid tumors has rapidly advanced over the past year. Increasing experience with the stable somatostatin analogue octreotide has enabled regulation of hormonal secretion by these tumors both chronically and during acute "carcinoid crisis." In addition, early identification may be facilitated by the use of isotopically labeled variants of the compound. Although the development of sophisticated pharmacotherapeutic probes has improved the management of secretory small intestinal tumors, the prognosis for adenocarcinomas, lymphomas, and sarcomas still primarily reflects on the time of delay in diagnosis and awaits an improved understanding of the pathobiology of these malignant lesions.

In conventional usage, "sepsis" denotes a clinical syndrome caused by excessive release of a variety of proinflammatory mediators, including tumor necrosis factor alpha, interleukin-1, and metabolites of arachidonic acid. Because this condition can be precipitated by infectious or noninfectious causes (eg, acute pancreatitis), a recent consensus conference has advocated replacing the term sepsis with the phrase systemic inflammatory response syndrome. Improvements in our understanding of the pathophysiologic basis for systemic inflammatory response syndrome have resulted in the development of a number of novel approaches for treating, preventing, or limiting its deleterious consequences. Although much of this work remains confined to the laboratory, several of these approaches are undergoing (or recently have undergone) clinical evaluation. Among these are the use of monoclonal antibodies against endotoxin, monoclonal antibodies against tumor necrosis factor, recombinant proteins that antagonize the effects of or bind to circulating interleukin-1 or tumor necrosis factor, and drugs that inhibit the enzyme cyclooxygenase, which is responsible for the formation of certain key metabolites of arachidonic acid.